Many functions of modern devices in automotive, consumer and industrial applications, such as converting electrical energy and driving an electric motor or an electric machine, rely on semiconductor devices. For example, Insulated Gate Bipolar Transistors (IGBTs), Metal Oxide Semiconductor Field Effect Transistors (MOSFETs), diodes and similar devices have been used for various applications including, but not limited to switches in power supplies and power converters.
For improving the switching behavior of such a semiconductor device and/or the efficiency of a power converter using such semiconductor devices, so-called superjunction structures have been introduced. Occasionally, semiconductor devices having such superjunction structure are also referred to as “compensation devices”, “CoolMOS™ devices”, “SJ devices” or “RESURF devices”. The superjunction structure is a charge compensation structure. For example, by means of a superjunction structure, the resistance in an epitaxial layer in a high voltage MOSFET can be substantially reduced, e.g., by a factor of greater than 5.
It is generally challenging producing a superjunction structure (which is also referred to as “compensation structure”) within a semiconductor device with sufficient accuracy, in particular with sufficient accuracy of a grade of charge compensation. Producing an accurate superjunction structure becomes even more challenging if the diffusion coefficient of the semiconductor body material is comparatively small.